Works might be a stretch. Every time I hear someone complaining about Time Machine it turns out they are trying to do it over SMB.

Yep. My household backs up to a Synology NAS via Time Machine: https://kb.synology.com/en-global/DSM/tutorial/How_to_back_u...

I’ve been using Time Machine with my synology nas for ~5 years. Works pretty well. I’d say once every 2 months it looses connection but seems to re-connect itself after a few minutes.

Since macOS 26, it’s SMB only. Time Machine over AFP is no longer supported.

For like 15 years.